A positioning technology is a technology adopted for determining a geographical location of a UE, which can directly or indirectly obtain the position information of the UE using resources of a wireless communication network. There are three standard manners for positioning a user equipment in a third generation partnership project long term evolution (3GPP LTE, Third Generation Partnership Project Long Term Evolution): network-assisted global navigation satellite system (GNSS, Global Navigation Satellite System) positioning, observed time difference of arrival (OTDOA, Observed Time Difference Of Arrival) positioning, and enhanced cell identification (e-CID, Enhanced Cell Identification) positioning.
A positioning algorithm for positioning a UE in the LTE is generally to detect characteristic parameters (such as signal field strength, a time difference of arrival of a propagation signal and an angle-of-arrival of a signal) of a radio wave propagation signal between the UE and a base station, and then estimate a location of the UE according to a relevant positioning algorithm. In the GNSS positioning method, the UE is required to have a wireless receiver for receiving a GNSS signal, and the GNSS can be specifically implemented as a global positioning system (GPS, Global Positioning System) positioning, a Galileo (Galileo) positioning, and etc. Both the OTDOA and the e-CID positioning are types of network positioning, and are mainly to detect characteristic parameters of radio resources within a mobile communication system, and then estimate the location of the UE according to a positioning algorithm. In the OTDOA positioning, the UE receives downlink positioning reference signals (PRS, Positioning Reference Signal) from a plurality of base stations, performs a timing measurement, and reports to a time difference of arrival for PRS between base stations, and a geographical location of the UE is obtained through calculation on a network positioning server. It is necessary for the OTDOA to perform a synchronization process between base stations before measurement.
The e-CID positioning is a positioning manner easily implemented in a cellular mobile communication. In a cell identification (CID, Cell Identification) positioning, each cell has its own specific cell identification (ID, Identification), when entering a certain cell, the UE needs to register in a current serving cell, and then there will be a corresponding cell ID in system data. The system determines the location of the UE according to the acquired ID of the cell where the UE is located. In the e-CID positioning, the current serving cell of the UE acquires information, such as round-trip time (RTT, Round Trip Time) of the UE, namely, timing advance (TA, Timing Advance), and angle of arrival (AOA, Angle of Arrival) etc. to further improve an accuracy of the positioning. As shown in FIG. 1, after acquiring the RTT of the UE, the serving cell can calculate a distance between a serving base station and the UE, and further determines the location of the UE by using the AOA between the serving base station and the UE, and the location of the serving base station.
As described above, the e-CID positioning technology adds AOA estimation and RTT estimation on the basis of the CID, and thus improves the accuracy of the positioning on the basis of the CID. However, a prerequisite for the serving base station to acquire the AoA information is that, the base station needs to be equipped with a smart antenna array, and a relatively higher requirement should be satisfied by the smart antenna. Therefore, in the e-CID positioning method, if there is no AoA value, only a distance S between the UE and the base station can be acquired just by the RTT information, that is, on the basis of the CID positioning, the UE is further defined on a circle or an arc centered at the current base station with a radius of S, and cannot be accurately positioned. In addition, only one serving base station measures the distance RTT and AoA, so the accuracy of the positioning will be affected when the smart antenna is in a lower accuracy or the communication environment changes.
Accordingly, there is a need to further improve the e-CID positioning in the prior art.